OAKLAND, Calif. (AP) _ Downtown business owners swept up broken glass and scrubbed graffiti Friday, as Oakland recovered from protests that splintered into rioting and looting after a white former transit officer was found guilty of killing an unarmed black man.

Debris littered street and some shops remained closed and boarded up along a one-mile strip where hundreds of protesters marched after a Los Angeles jury convicted former Bay Area Rapid Transit officer Johannes Mehserle of involuntary manslaughter on Thursday.

The initially peaceful demonstration turned violent after dark, with people breaking into an athletic wear store, ransacking a jewelry shop and setting trash can on fires as police in riot gear tried to clear the streets.

On Friday, Robert Reed opened his scooter shop next to the looted jewelry store, which remained closed. Reed said city officials had told business owners to prepare for possible riots, and most had heeded the warnings.

``They told us to board up. I don't know what he was thinking,'' Reed said of his neighbor.

In the end, about 30 businesses were damaged, but the city did not immediately release a damage estimate. Police said 78 people were arrested for violations that included failure to disperse, vandalism and assaulting a police officer.

Tony Coleman, who co-organized one of the two rallies outside City Hall, said he understood the range of reactions following the verdict.

``I would like to thank the city and the other protesters who expressed themselves in ways some think was wrong, for letting us have our space so that we ... could speak out,'' Coleman said.

Police Chief Anthony Batts said his officers had been careful to allow people to demonstrate peacefully, while containing the chaos so it wouldn't spread to other parts of the city. There were no serious injuries reported, he said.

``They conducted themselves in a very professional manner and I'm extremely proud of them and the job that they did,'' Batts said of police. ``They held their ground.''

Batts noted that about three-quarters of the arrestees had come from outside Oakland. He described them as ``anarchists'' who used the verdict as an excuse to cause trouble.

The high-profile case also sparked vandalism outside the city.

In Fresno, police said a memorial for dead police officers was defaced.

Near splatters of white paint thrown on the names of officers killed in the line of duty were leaflets saying ``Rest in peace, Oscar Grant'' from a small protest earlier in the day, said Todd Frazier, a board member of the Fresno County Peace Officers Memorial.

In Tacoma, Wash., KING-TV reported that a police officer's patrol car parked outside his home had been spray-painted overnight with the words ``Oscar Grant was here.'' The windows were smashed.

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AP Writer Trevor Hunnicutt in San Francisco contributed to this report.